Solar longitude
0°
Classification
Principal term · 气 qi
Month boundary
Does not open a month
Definition
What Spring Equinox marks
The season behind the name
Spring Equinox marks the balance around equal day and night, midway through the traditional spring season.
These names grew from seasonal observation and farming practice. They describe a traditional seasonal sequence, not a weather forecast for every region.
Spring Equinox begins at the instant the Sun reaches 0 degrees of apparent ecliptic longitude. It is one of 24 equal 15-degree divisions of the solar year, so its Gregorian position changes only slightly from year to year.
As a qi term, Spring Equinox marks the alternating mid-month point in the solar-term sequence. It does not open a solar branch month, and it does not open a lunar month.
The time is shown in China Standard Time (UTC+8). A reader west or east of that zone may see the same instant fall on a different local civil date.
Three pentads · 三候
Seasonal observations
Each traditional pentad spans about five days and names a seasonal sign associated with that part of the term.
- First pentad
Swallows arrive
玄鸟至
- Second pentad
Thunder begins to sound
雷乃发声
- Third pentad
Lightning begins to flash
始电

